As medical device technologies continue to evolve, neurostimulator devices have gained much popularity in the medical field. Neurostimulator devices include battery-powered or battery-less devices that are designed to deliver electrical stimulation to a patient. Through proper electrical stimulation, the neurostimulator devices can provide pain relief for patients.
Conventional neurostimulator devices may use a conductive enclosure to hermetically seal various components of the neurostimulator device therein. Such enclosure may be used to passively sink or source stimulation current in concert with a plurality of distal electrodes. For example, when a neurostimulator device operates in a monopolar mode, all of the activated distal electrodes (i.e., electrodes that are “turned on”) are driven with the same polarity while the enclosure is of the opposite polarity. As another example, when the neurostimulator device operates in a bipolar mode, the activated distal electrodes are programmed with either positive or negative polarity, and the enclosure is not used to sink or source any of the current. In other words, all current is sourced and sunk at the distal electrodes, and no current passes through the enclosure in the bipolar mode of operation. However, in these conventional neurostimulator devices, the enclosure itself is not programmable and cannot function as a controlled source of current in either the monopolar or the bipolar mode of operation. Such limitation may diminish the effectiveness and the flexibility of conventional neurostimulator devices.
Therefore, although existing neurostimulator devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.